CA2177320A1 - Method and probe arrangement for the electromagnetic detection of metal objects - Google Patents
Method and probe arrangement for the electromagnetic detection of metal objectsInfo
- Publication number
- CA2177320A1 CA2177320A1 CA002177320A CA2177320A CA2177320A1 CA 2177320 A1 CA2177320 A1 CA 2177320A1 CA 002177320 A CA002177320 A CA 002177320A CA 2177320 A CA2177320 A CA 2177320A CA 2177320 A1 CA2177320 A1 CA 2177320A1
- Authority
- CA
- Canada
- Prior art keywords
- probe arrangement
- loops
- loop
- signals
- receiving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/885—Radar or analogous systems specially adapted for specific applications for ground probing
Abstract
A method and probe arrangement are disclosed for the electromagnetic detection of metal objects. An electromagnetic signal is emitted for exciting a metal object, causing the object to emit a secondary signal which is received by a plurality of receiving loops of the probe arrangement. The loops are interconnected to produce a series of interconnection signals in an object-specific manner. The interconnection signals are evaluated and displayed. The probe arrangement may have a transmitting loop surrounding the receiving loops, and the transmitting loop may also function as a receiving loop. The receiving loops may be arranged in a matrix-like manner, and may also be grouped into a series of main receiving loops.
Each main receiving loop functions as a receiving loop that is additional to thereceiving loops comprising it.
Each main receiving loop functions as a receiving loop that is additional to thereceiving loops comprising it.
Description
-METHOD AND PROBE ARRANGEMENT FOR THE
ELECTROMAGNETIC DETECTION OF METAL OBJECTS
The invention relates to a method and to a probe arrangement for the electromagnetic detection of metal objects. In particular, it relates to a method and probe arrangement in which an electromagnetic signal is emitted to excite an object to be detected to emit a secondary signal, which is then 5 received by a plurality of loops to form loop-specific secondary signals which are evaluated in an object-specific manner and displayed.
German Patent Application No. 42 42 541 of TZN Forschungs- und Entwicklungszentrum Unterluss GmbH, which has a publication date of June 30, 1994, discloses a method and a probe arrangement of the aforementioned type.
10 Within a support device four juxtaposed transmitting and receiving coils are moved over an area to be examined, allowing a larger surface to be scanned.
The information of each individual coil is sensed and supplied for processing.
With this known method and probe arrangement there is parallel scanning by four independent transmitting and receiving coils. The signal 15 evaluation is not of an optimum nature, and it would be desirable if positioninformation on the object could be detected with greater accuracy and over a wider range.
The object of the invention is to provide a method and a probe arrangement of the aforementioned type which leads to a particularly good 20 evaluation of the signal information and to very precise position detection of the sought object.
One form of the invention for achieving this object is a method comprising the steps of emitting an electromagnetic signal for exciting a metal object so that the object emits a secondary signal, receiving the secondary 25 signal using a plurality of loops to form loop-specific secondary signals, interconnecting in an object-specific manner the loop-specific secondary signalsto produce a series of interconnection signals, evaluating the interconnection signals, and displaying the result of the evaluating step. The loop-specific secondary signals may be stored and then jointly evaluated. The interconnecting step may involve the adding or subtracting of the secondary signals. In this method, one part of the loop-specific secondary signal may be summed to a first sum and a further part of those secondary signals summed to a second sum, and a differential signal then formed from the two sums. The loop-specific secondary signals to be summed may be selected as a function of a subsoil to which the method is applied. The emitted electromagnetic signal may be a single pulse with a frequency of 10 Hz to 10 kHz, or the signal may involve bipolar pulses. Individual secondary sampling signals with predeterminable sampling times may be produced from each loop-specific secondary signal, wherein the sampling signals are interconnected by addition and/or subtraction to produce a result, and that result is supplied to further processing as a prepared secondary signal. The interconnection and evaluation steps may be performed digitally under microprocessor control.
Another form of the invention is a probe arrangement which comprises a plurality of loops constructed as receiving loops for the reception of magnetic field signals for performing the electromagnetic detection method previously described. The receiving loops are arranged in a matrix-like manner.
The probe arrangement also comprises a transmitting loop constructed to surround the matrix-like arrangement of receiving loops. The receiving loops may be arranged in the form of a bidimensional matrix. A plurality of receiving loops may be combined to form a main loop. In such arrangement, there may be four main loops and each main loop comprises four receiving loops.
Alternatively, there may be four main loops and each main loop comprises eight receiving loops. The transmitting loop may be constructed so as to also function as a receiving loop. Each of the receiving loops may be connected to a sample-and-hold device for scanning and storing scanned signals of the received secondary signal, and the transmitting loop may also be connected to a sample-and-hold device for such scanning and storing. The sample-and-hold device may comprise analog switches and capacitors.
The probe arrangement may further comprise a multiplexer for sensing, as a function of a search task, selected ones of the receiving loops.
-The probe arrangement may be located in a vertically-adjustable, portable apparatus, or in a floatable apparatus, or in a submersible apparatus. The receiving loops may be of different sizes.
In accordance with an essential basic concept of the invention, an 5 electromagnetic signal is emitted which excites the object to be detected to emit a secondary signal to a number of receiving loops. The received signals are interconnected and evaluated in a planned manner. In the probe arrangement several receiving loops are arranged in a matrix-like manner, and in each case they are able to receive the secondary signal emitted by the object to be 10 detected. As a result of the different distances and spatial arrangement of the different receiving loops with respect to the object, loop-specific secondary signals differing from one another are measured. These different measured values are then interconnected or compared, so as to obtain precise information on the location and position of the object to be detected.
It is advantageous to initially store the secondary signals received and then jointly evaluate them. However, it is equally possible to supply each individual secondary signal to the interconnection, where it is intermediately stored until processed with the next received secondary signal. Preferably, addition and subtraction take place when evaluating the secondary signals.
20 Thus, all the received secondary signals can be summed in order to obtain a stronger location signal than would be possible when processing a single signal.However, it is preferable to sum one part of the received secondary signals so as to form a first sum, then to sum a further part of the received secondary signals to form a second sum, and then to form a differential signal from the two 25 sums. In this way, it is possible to obtain information on the precise location and position of the object to be detected. Thus, with this method, it is not only possible to determine relative conductivity changes in the ground, but also spatially-distributed electrical differences. From subtracting a number of secondary signals, information on direction may be obtained; from that 30 information, the complete probe arrangement may be automatically tracked in that direction.
As a result of the spatial nature, as well as the measurement and processing of the individual secondary signals received, it is possible to produce computer-assisted shadow images of the search objects. It is preferable to so select which secondary signals are to be received and summed so that ground 5 or soil compensation is automatically performed. For this purpose, two groups of secondary signals must be selected, which in the absence of an object to be sought give in a soil-specific manner the same sum. The difference of the two groups consequently gives "zero" for as long as no object modifies the received secondary signal, and consequently gives rise to a result differing from "zero".10 This can, for example, take place by subtraction of two directlyjuxtaposed receiving loops.
The method is preferably performed in pulse-induction (Pl) technology. Frequencies between 10 Hz and 10 kHz can be used. However, it is preferable to use bipolar pulses, and it is also possible to adopt continuous 1 5 operation.
When using single pulses it is particularly preferable to initially scan each received signal individually with a sampling and multiplexing process,and to process the scanned values. This can be performed for the scanned values of each individual received secondary signal in the same way, as 20 described hereinbefore for all the secondary signals. Thus, in each receivingchannel is obtained a secondary signal which has already been prepared and processed. Thus, for example, on summing the individual scanned values, secondary signals are obtained that each have up to 30% increased sensitivity compared with the normal received secondary signal. With the thus-prepared 25 individual values is carried out the further method and the interconnection of the received and prepared secondary signals. Although this can be performed with mono-single pulses, it is preferably performed with bipolar single pulses. It isalso preferable to evaluate with digital methods and microprocessors, in order to be able to utilize the multiplicity of available measurement and 30 interconnection possibilities.
For performing the method, the invention provides a probe arrangement with several receiving loops arranged in matrix-like manner and around which is formed a transmitting loop. It is advantageous in this arrangement that a large transmitting loop is used which is able to pass around 5 the receiving loops and to transmit a wide magnetic field into the ground, so that the penetration depth of the magnetic field into the ground is increased. It is also technically advantageous to work with separate transmitting and receiving loops.
Preferably the receiving loops are in the form of a bidimensional 10 matrix, which in the smallest case is a 2x2 matrix. As a result of the evaluation of receiving loops arranged in this way, it is possible to achieve a more precise position and depth finding with respect to the object. There is preferably a separate sensing of the receiving coils in the 'x' and 'y' directions. It is possible to detect object concentrations at certain locations of the loop, with the search 1 5 route.
The receiving loops can be further subdivided. Individual receiving loops can be interlocked to form a so-called main loop. In such case the individual receiving loops and also the main loop are sensed as a whole, and their values can be compared with one another and interconnected. In a 20 preferred embodiment there are four main loops, whereof each comprises four or eight receiving loops. The advantage of this arrangement is that, as a resultof the size of the receiving loops, an adaptation to the search task is possible.
If only large objects are sought, it is sufflcient to merely sense the values of the main loops. However, with smaller search objects it becomes necessary to 25 sense smaller search loops. The depth range can also be controlled by the choice and use of the receiving loops.
According to a further development of the invention, the large transmitting loop is so constructed that it can both transmit and receive. That received value can be related to the individual received secondary signals, and 30 consequently an additional interconnection can be brought about, leading to increased measurement precision. The diameter of the large transmitting loops -can, for example! be between 0.5 and 5 metres. Conversely, there are cases where it is preferable to construct the small receiving loops and/or main loops as transmitting loops.
In a preferred embodiment of the probe arrangement, each of the 5 receiving loops and each of the main loops and also the transmitting loop (when used as a receiving loop) is connected to a sample-and-hold device for scanning and storing the received secondary signals. The sample-and-hold devices have analog switches and capacitors.
According to a further developement of the invention, it is also 10 possible to use receiving loops of different sizes. ~Ithin a main loop there can be, for example, a very large receiving loop and several smaller receiving loopsarranged around the latter. Thus, with the larger receiving loop a higher sensitivity can be obtained, the smaller receiving loops then being used for locating positions more precisely.
Advantageously, the complete probe arrangement is housed in a portable or travelling, metal-free apparatus, where it is possible to adjust theloop height with respect to the ground. Adjustability offers the advantage that the influence of highly-interfering soils can be reduced by a greater measuring distance. In addition, to a certain extent small metal parts can be masked out.
20 Such a masking out of undesired parts can also take place through a computer-controlled signal selection. In certain cases it is also possible to use a floatable and/or submersible construction of the probe arrangement when seeking objects under water. For this purpose, the probe arrangement with the associated electronics is placed in a watertight, encapsulated casing. The results are 25 displayed in a display which can be seen by the user and is controllable fromthe probe arrangement by radio or cable connection. The floatable and submersible probe arrangement is equipped with floodable tanks, with which the buoyancy or submersion depth can be controlled.
The invention will next be described in greater detail with reference 30 to Figure 1, which is a block circuit diagram illustrating the operation of the probe arrangement.
2~ 77320 Figure 1 is a block circuit diagram of a probe arrangement, which shows a transmiKing loop 1 connected to a transmiKer 11. The transmiKer produces single pulses, which can be emiKed far into the ground over the large surrounding transmiKing loop 1. The receiving loops 2 are arranged in matrix-5 like manner within the transmiKing loop 1. Each of the receiving loops forms areceiving channel. In each case, eight individual receiving loops 2 are combined to form a main loop 3, which can form a further receiving channel.
Since the transmiKing loop 1 is also constructed as an additional receiving channel, there are in all 37 receiving channels -- 32 for the individual receiving 10 loops 2, four for the main loops 3, and one receiving channel on the transmiKing loop 1. The main loops 3 are connected to the multiplexer 5, which senses the 37 receiving channels. In other words, the 37 secondary signals are received and supplied to an interconnection of the individual values for further processing. The loops are normally constructed as coils.
The preparation of the individual measured values, which are received by a data logger during the search and are intermediately stored, takesplace at a later time by computer-assisted processing. The documented search process can be implemented in random form by suitable software. A direct, analog display during the search is also possible, for example, an indication of20 the part of the loop in which there are metal objects.
It can be gathered from Figure 1 that the individual receiving loops 2, and also the main loops 3, have in each case a receiver 6 and a sample-and-hold device with analog switches 7 and capacitors 8 for time-related and/or amplitude-related scanning and intermediate storage of secondary signals.
ELECTROMAGNETIC DETECTION OF METAL OBJECTS
The invention relates to a method and to a probe arrangement for the electromagnetic detection of metal objects. In particular, it relates to a method and probe arrangement in which an electromagnetic signal is emitted to excite an object to be detected to emit a secondary signal, which is then 5 received by a plurality of loops to form loop-specific secondary signals which are evaluated in an object-specific manner and displayed.
German Patent Application No. 42 42 541 of TZN Forschungs- und Entwicklungszentrum Unterluss GmbH, which has a publication date of June 30, 1994, discloses a method and a probe arrangement of the aforementioned type.
10 Within a support device four juxtaposed transmitting and receiving coils are moved over an area to be examined, allowing a larger surface to be scanned.
The information of each individual coil is sensed and supplied for processing.
With this known method and probe arrangement there is parallel scanning by four independent transmitting and receiving coils. The signal 15 evaluation is not of an optimum nature, and it would be desirable if positioninformation on the object could be detected with greater accuracy and over a wider range.
The object of the invention is to provide a method and a probe arrangement of the aforementioned type which leads to a particularly good 20 evaluation of the signal information and to very precise position detection of the sought object.
One form of the invention for achieving this object is a method comprising the steps of emitting an electromagnetic signal for exciting a metal object so that the object emits a secondary signal, receiving the secondary 25 signal using a plurality of loops to form loop-specific secondary signals, interconnecting in an object-specific manner the loop-specific secondary signalsto produce a series of interconnection signals, evaluating the interconnection signals, and displaying the result of the evaluating step. The loop-specific secondary signals may be stored and then jointly evaluated. The interconnecting step may involve the adding or subtracting of the secondary signals. In this method, one part of the loop-specific secondary signal may be summed to a first sum and a further part of those secondary signals summed to a second sum, and a differential signal then formed from the two sums. The loop-specific secondary signals to be summed may be selected as a function of a subsoil to which the method is applied. The emitted electromagnetic signal may be a single pulse with a frequency of 10 Hz to 10 kHz, or the signal may involve bipolar pulses. Individual secondary sampling signals with predeterminable sampling times may be produced from each loop-specific secondary signal, wherein the sampling signals are interconnected by addition and/or subtraction to produce a result, and that result is supplied to further processing as a prepared secondary signal. The interconnection and evaluation steps may be performed digitally under microprocessor control.
Another form of the invention is a probe arrangement which comprises a plurality of loops constructed as receiving loops for the reception of magnetic field signals for performing the electromagnetic detection method previously described. The receiving loops are arranged in a matrix-like manner.
The probe arrangement also comprises a transmitting loop constructed to surround the matrix-like arrangement of receiving loops. The receiving loops may be arranged in the form of a bidimensional matrix. A plurality of receiving loops may be combined to form a main loop. In such arrangement, there may be four main loops and each main loop comprises four receiving loops.
Alternatively, there may be four main loops and each main loop comprises eight receiving loops. The transmitting loop may be constructed so as to also function as a receiving loop. Each of the receiving loops may be connected to a sample-and-hold device for scanning and storing scanned signals of the received secondary signal, and the transmitting loop may also be connected to a sample-and-hold device for such scanning and storing. The sample-and-hold device may comprise analog switches and capacitors.
The probe arrangement may further comprise a multiplexer for sensing, as a function of a search task, selected ones of the receiving loops.
-The probe arrangement may be located in a vertically-adjustable, portable apparatus, or in a floatable apparatus, or in a submersible apparatus. The receiving loops may be of different sizes.
In accordance with an essential basic concept of the invention, an 5 electromagnetic signal is emitted which excites the object to be detected to emit a secondary signal to a number of receiving loops. The received signals are interconnected and evaluated in a planned manner. In the probe arrangement several receiving loops are arranged in a matrix-like manner, and in each case they are able to receive the secondary signal emitted by the object to be 10 detected. As a result of the different distances and spatial arrangement of the different receiving loops with respect to the object, loop-specific secondary signals differing from one another are measured. These different measured values are then interconnected or compared, so as to obtain precise information on the location and position of the object to be detected.
It is advantageous to initially store the secondary signals received and then jointly evaluate them. However, it is equally possible to supply each individual secondary signal to the interconnection, where it is intermediately stored until processed with the next received secondary signal. Preferably, addition and subtraction take place when evaluating the secondary signals.
20 Thus, all the received secondary signals can be summed in order to obtain a stronger location signal than would be possible when processing a single signal.However, it is preferable to sum one part of the received secondary signals so as to form a first sum, then to sum a further part of the received secondary signals to form a second sum, and then to form a differential signal from the two 25 sums. In this way, it is possible to obtain information on the precise location and position of the object to be detected. Thus, with this method, it is not only possible to determine relative conductivity changes in the ground, but also spatially-distributed electrical differences. From subtracting a number of secondary signals, information on direction may be obtained; from that 30 information, the complete probe arrangement may be automatically tracked in that direction.
As a result of the spatial nature, as well as the measurement and processing of the individual secondary signals received, it is possible to produce computer-assisted shadow images of the search objects. It is preferable to so select which secondary signals are to be received and summed so that ground 5 or soil compensation is automatically performed. For this purpose, two groups of secondary signals must be selected, which in the absence of an object to be sought give in a soil-specific manner the same sum. The difference of the two groups consequently gives "zero" for as long as no object modifies the received secondary signal, and consequently gives rise to a result differing from "zero".10 This can, for example, take place by subtraction of two directlyjuxtaposed receiving loops.
The method is preferably performed in pulse-induction (Pl) technology. Frequencies between 10 Hz and 10 kHz can be used. However, it is preferable to use bipolar pulses, and it is also possible to adopt continuous 1 5 operation.
When using single pulses it is particularly preferable to initially scan each received signal individually with a sampling and multiplexing process,and to process the scanned values. This can be performed for the scanned values of each individual received secondary signal in the same way, as 20 described hereinbefore for all the secondary signals. Thus, in each receivingchannel is obtained a secondary signal which has already been prepared and processed. Thus, for example, on summing the individual scanned values, secondary signals are obtained that each have up to 30% increased sensitivity compared with the normal received secondary signal. With the thus-prepared 25 individual values is carried out the further method and the interconnection of the received and prepared secondary signals. Although this can be performed with mono-single pulses, it is preferably performed with bipolar single pulses. It isalso preferable to evaluate with digital methods and microprocessors, in order to be able to utilize the multiplicity of available measurement and 30 interconnection possibilities.
For performing the method, the invention provides a probe arrangement with several receiving loops arranged in matrix-like manner and around which is formed a transmitting loop. It is advantageous in this arrangement that a large transmitting loop is used which is able to pass around 5 the receiving loops and to transmit a wide magnetic field into the ground, so that the penetration depth of the magnetic field into the ground is increased. It is also technically advantageous to work with separate transmitting and receiving loops.
Preferably the receiving loops are in the form of a bidimensional 10 matrix, which in the smallest case is a 2x2 matrix. As a result of the evaluation of receiving loops arranged in this way, it is possible to achieve a more precise position and depth finding with respect to the object. There is preferably a separate sensing of the receiving coils in the 'x' and 'y' directions. It is possible to detect object concentrations at certain locations of the loop, with the search 1 5 route.
The receiving loops can be further subdivided. Individual receiving loops can be interlocked to form a so-called main loop. In such case the individual receiving loops and also the main loop are sensed as a whole, and their values can be compared with one another and interconnected. In a 20 preferred embodiment there are four main loops, whereof each comprises four or eight receiving loops. The advantage of this arrangement is that, as a resultof the size of the receiving loops, an adaptation to the search task is possible.
If only large objects are sought, it is sufflcient to merely sense the values of the main loops. However, with smaller search objects it becomes necessary to 25 sense smaller search loops. The depth range can also be controlled by the choice and use of the receiving loops.
According to a further development of the invention, the large transmitting loop is so constructed that it can both transmit and receive. That received value can be related to the individual received secondary signals, and 30 consequently an additional interconnection can be brought about, leading to increased measurement precision. The diameter of the large transmitting loops -can, for example! be between 0.5 and 5 metres. Conversely, there are cases where it is preferable to construct the small receiving loops and/or main loops as transmitting loops.
In a preferred embodiment of the probe arrangement, each of the 5 receiving loops and each of the main loops and also the transmitting loop (when used as a receiving loop) is connected to a sample-and-hold device for scanning and storing the received secondary signals. The sample-and-hold devices have analog switches and capacitors.
According to a further developement of the invention, it is also 10 possible to use receiving loops of different sizes. ~Ithin a main loop there can be, for example, a very large receiving loop and several smaller receiving loopsarranged around the latter. Thus, with the larger receiving loop a higher sensitivity can be obtained, the smaller receiving loops then being used for locating positions more precisely.
Advantageously, the complete probe arrangement is housed in a portable or travelling, metal-free apparatus, where it is possible to adjust theloop height with respect to the ground. Adjustability offers the advantage that the influence of highly-interfering soils can be reduced by a greater measuring distance. In addition, to a certain extent small metal parts can be masked out.
20 Such a masking out of undesired parts can also take place through a computer-controlled signal selection. In certain cases it is also possible to use a floatable and/or submersible construction of the probe arrangement when seeking objects under water. For this purpose, the probe arrangement with the associated electronics is placed in a watertight, encapsulated casing. The results are 25 displayed in a display which can be seen by the user and is controllable fromthe probe arrangement by radio or cable connection. The floatable and submersible probe arrangement is equipped with floodable tanks, with which the buoyancy or submersion depth can be controlled.
The invention will next be described in greater detail with reference 30 to Figure 1, which is a block circuit diagram illustrating the operation of the probe arrangement.
2~ 77320 Figure 1 is a block circuit diagram of a probe arrangement, which shows a transmiKing loop 1 connected to a transmiKer 11. The transmiKer produces single pulses, which can be emiKed far into the ground over the large surrounding transmiKing loop 1. The receiving loops 2 are arranged in matrix-5 like manner within the transmiKing loop 1. Each of the receiving loops forms areceiving channel. In each case, eight individual receiving loops 2 are combined to form a main loop 3, which can form a further receiving channel.
Since the transmiKing loop 1 is also constructed as an additional receiving channel, there are in all 37 receiving channels -- 32 for the individual receiving 10 loops 2, four for the main loops 3, and one receiving channel on the transmiKing loop 1. The main loops 3 are connected to the multiplexer 5, which senses the 37 receiving channels. In other words, the 37 secondary signals are received and supplied to an interconnection of the individual values for further processing. The loops are normally constructed as coils.
The preparation of the individual measured values, which are received by a data logger during the search and are intermediately stored, takesplace at a later time by computer-assisted processing. The documented search process can be implemented in random form by suitable software. A direct, analog display during the search is also possible, for example, an indication of20 the part of the loop in which there are metal objects.
It can be gathered from Figure 1 that the individual receiving loops 2, and also the main loops 3, have in each case a receiver 6 and a sample-and-hold device with analog switches 7 and capacitors 8 for time-related and/or amplitude-related scanning and intermediate storage of secondary signals.
Claims (24)
1. A method for an electromagnetic detection of metal objects, comprising the steps of:
emitting an electromagnetic signal for exciting the metal object, the excitation causing the object to emit a secondary signal;
receiving the secondary signal using a plurality of loops to form loop-specific secondary signals;
interconnecting the loop-specific secondary signals to produce a series of interconnection signals, the interconnecting step being performed in an object-specific manner;
evaluating the interconnection signals; and, displaying the result of the evaluating step.
emitting an electromagnetic signal for exciting the metal object, the excitation causing the object to emit a secondary signal;
receiving the secondary signal using a plurality of loops to form loop-specific secondary signals;
interconnecting the loop-specific secondary signals to produce a series of interconnection signals, the interconnecting step being performed in an object-specific manner;
evaluating the interconnection signals; and, displaying the result of the evaluating step.
2. A method according to claim 1, wherein the loop-specific secondary signals are stored and then jointly evaluated.
3. A method according to claim 1, wherein the interconnecting step involves the adding or subtracting of the secondary signals.
4. A method according to claim 1, wherein one part of the loop-specific secondary signals is summed to a first sum, wherein a further part of those secondary signals is summed to a second sum, and wherein a differential signal is formed from the two sums.
5. A method according to claim 4, wherein the loop-specific secondary signals to be summed are selected as a function of a subsoil to which the methodis applied.
6. A method according to claim 1, wherein the emitted electromagnetic signal is a single pulse with a frequency of 10 Hz to 10 kHz.
7. A method according to claim 1, wherein the emitted electromagnetic signal involves bipolar pulses.
8. A method according to claim 6, wherein individual secondary sampling signals with predeterminable sampling times are produced from each loop-specificsecondary signal, wherein the sampling signals are interconnected by addition and/or subtraction to produce a result, and that result is supplied to further processing as a prepared secondary signal.
9. A method according to claim 1, wherein the interconnection and evaluation steps are performed digitally under microprocessor control.
10. A probe arrangement for the electromagnetic detection of metal objects, the probe arrangement comprising a plurality of loops constructed as receiving loops for the reception of magnetic field signals for performing the method according to claim 1, the receiving loops being arranged in a matrix-like manner, the probe arrangement also comprising a transmitting loop constructed to surround the matrix-like arrangement of receiving loops.
11. A probe arrangement as in claim 10, wherein the receiving loops are arranged in the form of a bidimensional matrix.
12. A probe arrangement as in claim 10, wherein a plurality of receiving loops are combined to form a main loop.
13. A probe arrangement as in claim 10, wherein there are four main loops and each main loop comprises four receiving loops.
14. A probe arrangement as in claim 10, wherein there are four main loops and each main loop comprises eight receiving loops.
15. A probe arrangement as in claim 10, wherein the transmitting loop is constructed so as to also function as a receiving loop.
16. A probe arrangement as in claim 10, wherein each of the receiving loops is connected to a sample-and-hold device for scanning and storing scanned signals of the received secondary signal.
17. A probe arrangement as in claim 12, wherein each of the receiving loops is connected to a sample-and-hold device for scanning and storing scanned signals of the received secondary signal.
18. A probe arrangement as in claim 15, wherein the transmitting loop is connected to a sample-and-hold device for scanning and storing scanned signals of the received secondary signal.
19. A probe arrangement as in claim 16, wherein the sample-and-hold device comprises analog switches and capacitors.
20. A probe arrangement as in claim 10, and also comprising a multiplexer for sensing, as a function of a search task, selected ones of the receiving loops.
21. A probe arrangement as in claim 10, wherein the probe arrangement is located in a vertically-adjustable, portable apparatus.
22. A probe arrangement as in claim 10, wherein the probe arrangement is located in a floatable apparatus.
23. A probe arrangement as in claim 10, wherein the receiving loops are of different sizes.
24. A probe arrangement as in claim 10, wherein the probe arrangement is located in a submersible apparatus.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19518342.8 | 1995-05-18 | ||
| DE19518342A DE19518342A1 (en) | 1995-05-18 | 1995-05-18 | Method and probe arrangement for the electromagnetic detection of metallic objects |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2177320A1 true CA2177320A1 (en) | 1996-11-19 |
Family
ID=7762299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002177320A Abandoned CA2177320A1 (en) | 1995-05-18 | 1996-05-17 | Method and probe arrangement for the electromagnetic detection of metal objects |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5770944A (en) |
| EP (1) | EP0743539A3 (en) |
| CA (1) | CA2177320A1 (en) |
| DE (1) | DE19518342A1 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6600320B2 (en) * | 1996-03-25 | 2003-07-29 | The Johns Hopkins University | Apparatus with movable receiver coil array for locating a buried metallic object |
| US6064209A (en) * | 1998-05-18 | 2000-05-16 | Xtech Explosive Decontamination, Inc. | Apparatus and process for clearance of unexploded ordinance |
| DE29903856U1 (en) * | 1999-03-03 | 1999-06-10 | Ebinger Klaus Ing Fa | Probe arrangement |
| DE10155533C2 (en) * | 2001-11-12 | 2003-12-18 | Andreas Roser | Device for locating land or sea mines |
| DE10213115A1 (en) * | 2002-03-23 | 2003-10-16 | Lorenz Roatzsch | Detecting objects, especially metal objects, using individual pulse-induction probes to detect induction signals from objects and evaluating variations in induction signals emitted by object |
| ATE545047T1 (en) | 2002-03-23 | 2012-02-15 | Lorenz Roatzsch | METHOD FOR DETECTING OBJECTS, IN PARTICULAR METAL OBJECTS |
| DE10240293B4 (en) * | 2002-08-31 | 2007-05-24 | Bundesrepublik Deutschland, vertreten durch das Bundesministerium der Verteidigung, dieses vertreten durch den Präsidenten des Bundesamtes für Wehrtechnik und Beschaffung | mine-clearing |
| DE102004047188B4 (en) | 2004-09-29 | 2022-10-27 | Robert Bosch Gmbh | Device for locating metallic objects |
| US8098070B2 (en) * | 2008-06-05 | 2012-01-17 | Lopez John A | Electromagnetic subterranean imaging instrument |
| KR20150083593A (en) * | 2014-01-10 | 2015-07-20 | 한국전자통신연구원 | Apparatus and method for detecting position of buried pipes |
| CN111323825B (en) * | 2020-03-23 | 2022-09-20 | 西安西北有色物化探总队有限公司 | Ground-pit wide-area electromagnetic detection method and device |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2041532B (en) * | 1979-01-31 | 1983-05-11 | Plessey Co Ltd | Metal detector |
| JPS5646480A (en) * | 1979-09-25 | 1981-04-27 | Nec Corp | Magnetic sign system |
| DE3421066A1 (en) * | 1984-06-06 | 1986-01-02 | Heimann Gmbh, 6200 Wiesbaden | Person inspection device |
| DE3705308A1 (en) * | 1987-02-19 | 1988-09-01 | Foerster Inst Dr Friedrich | INDUCTIVE SEARCH DEVICE |
| US4818944A (en) * | 1987-05-06 | 1989-04-04 | Schonstedt Instrument Company | Magnetic locating and tracing system and method using dual-antenna transmitter to distinguish between concealed adjacent objects |
| US4912414A (en) * | 1988-10-28 | 1990-03-27 | Lesky Edward S | Induction-type metal detector with increased scanning area capability |
| DE4242541C2 (en) * | 1992-12-16 | 1996-03-28 | Tzn Forschung & Entwicklung | Device for locating ammunition located below the earth's surface |
| DE4326030A1 (en) * | 1993-08-03 | 1995-02-09 | Klaus Ebinger | Method for the electromagnetic detection of objects |
-
1995
- 1995-05-18 DE DE19518342A patent/DE19518342A1/en not_active Withdrawn
-
1996
- 1996-05-14 US US08/645,792 patent/US5770944A/en not_active Expired - Fee Related
- 1996-05-17 EP EP96107936A patent/EP0743539A3/en not_active Withdrawn
- 1996-05-17 CA CA002177320A patent/CA2177320A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0743539A2 (en) | 1996-11-20 |
| EP0743539A3 (en) | 1999-06-16 |
| DE19518342A1 (en) | 1996-11-21 |
| US5770944A (en) | 1998-06-23 |
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| Date | Code | Title | Description |
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| FZDE | Discontinued |